In recent years, portable fuel cell power systems have received consideration as replacements or alternatives to the battery power systems currently utilized on industrial electric vehicles and panel trucks. One exemplary industrial sector where the portable and self-contained fuel cell power systems have proven useful involves panel trucks that require an additional source of electrical power in addition to the electrical power that may be supplied from an alternator or generator running off the internal combustion engine. When the engine is not running, the alternative source of electricity can be used to power electronic devices and/or motors which drive the mechanical, hydraulic, or pneumatic systems which are also carried on the truck.
Another sector where portable fuel cell power systems have made significant progress is within the specialized industrial electric trucks and vehicles market that includes fork trucks, tractors, platform lift trucks, hand trucks, and floor cleaners, etc. These specialize trucks are typically used for materials handling and site maintenance in indoor warehouses, processing and manufacturing facilities, and other areas which must comply with emissions regulations and fire safety standards. In contrast to their battery-powered predecessors, fuel cell-powered industrial trucks do not require down time and floor space for recharging, and are generally available for operation 24 hours a day, 7 days a week. Thus, in switching from a battery-based system to a fuel cell-based system, the user may be able to save time and floor space, as well as reduce the number of specialized industrial electric trucks required to operate his business safely and efficiently.
Portable and self-contained fuel cell power systems generally include a reservoir where the fuel is stored, and one or more fuel cells arranged in a fuel cell stack that convert the chemical energy in the fuel into electricity in an electrochemical process. In doing so, however, the fuel call may also produce a generous amount of heat, and it is common for the temperatures of the outer surfaces of the fuel cell to range from 300° C. to 750° C. The preferred fuel is generally some form of hydrogen that may be stored in either a gaseous state or in a liquid state (e.g. methanol), while the non-electrical by-products of the electrochemical process are primarily the waste heat and water vapor, with possible additional non-volatile gases included with the water vapor, depending on the type of fuel. While the water vapor (and other gases) is usually released into the surrounding environment, the waste heat from the fuel cell must be controlled to prevent hot spots that could damage adjacent equipment and structures, or that could inadvertently initiate combustion if operated near a combustible material or gas. This is typically accomplished through the use of a sealed container that houses a body of insulting material that surrounds and conforms to the irregular shape of the fuel cell, and that redistributes the heat as it flows from the outer surface of the fuel cell, through the insulating material, and eventually to the outer surface of the container where it is dissipated into the surrounding environment. The insulating material is generally configured to redistribute the waste heat more evenly across the outer surface area of the container and to reduce the intensity of any hot spots on the outer surface of the container.
In current fuel cell containers, the body of insulating material is generally machined from a solid block of insulating material to match the irregular profile of the fuel cell and to provide the greatest amount of heat redistribution in the smallest possible space, given the size and spacing limitations in typical vehicle applications. However, both the “machineable” insulation material and the machining process can be expensive and the consuming, which often results in a more expensive portable power system having longer delivery times. Consequently, a need exists for a more affordable, cost-effective, and easily-manufactured insulating container for an active fuel cell that may be used in a vehicular application, and which effectively controls the heat transfer through the container to avoid hot spots on the outside of the container. It is toward such an insulating container that the present disclosure is directed.